1. Field of the Invention
The present invention is related in general to a backlight module and, more particularly, to a backlight module with a fan being disposed on a lateral plate of the frame.
2. Description of the Related Art
Along with the rapid advance in the manufacturing technology and the features of slimness, power-saving and low radiation, liquid crystal displays (LCDs) has been widely applied in electronic products such as personal digital assistant (PDA), notebook computer, digital camera, digital video recorder, mobile phone, computer monitor and liquid crystal TV. In a LCD, the LCD panel is non-luminous and needs a backlight module to provide a light source to facilitate display function.
Referring to FIG. 1, a cross-sectional view of a conventional LCD is shown. In FIG. 1, the LCD 9 comprises an LCD panel 8a and a backlight module 8b. The backlight module 8b comprises a frame 2, a reflector 3, a light source comprising a plurality of cold cathode fluorescent lamps (CCFLs) 4, and an optical film comprising a diffuser plate 5, a diffuser piece 7 and a prism 6. The frame 2, whose top surface has an accommodation space 2a disposed thereon, has a bottom-plate's inner surface 2b and two lateral-plate's inner surfaces 2c. The reflector 3 is positioned in the accommodation space 2a to be disposed on the bottom-plate's inner surface 2b and two lateral-plate's inner surface 2c. The plurality of CCFLs 4 are lined up in the accommodation space 2a and positioned above the reflector 3. The diffuser plate 5 is disposed above the plurality of CCFLs 4. The prism 6 is disposed on the diffuser plate 5. The diffuser piece 7 is disposed on the prism 6. The LCD panel 8a is disposed on the diffuser piece 7. Firstly, the light generated by the plurality of CCFLs 4 are projected onto the diffuser plate 5 via the reflection of the reflector 3. Then, the light which has been processed by the diffuser plate 5, the prism 6 and the diffuser piece 7 is projected onto the LCD panel 8a directly.
The CCFL generates high temperature when generating light. A conventional backlight module normally adopts natural convection to ventilate the generated heat. However, as a higher standard of LCD luminance is requested, a larger amount of heat is generated from the light sources. Consequently, the average temperature of the backlight module is increased. The luminance quality of CCFL is deteriorated and mura effect is more likely to occur to the LCD if the CCFL is exposed to a working environment of high temperature. Similarly, the backlight module using a light emitting diode (LED) as the light source also faces the same problem when a higher standard of LCD luminance is requested.